This invention relates to a visual display device, and more particularly, to a flat panel electronic color display using stacks of voltage positionable colored membranes.
A visual electronic display device consists of optical, mechanical, and electronic parts in an assembly that accepts data in an electronic form and provides a visual display of the data to an observer. In current society visual electronic displays are ubiquitous, being a requirement of every television set, every computer, and many dedicated products. Early display devices were limited to Black and White or monochrome. As color became available it quickly became the technology of choice. Of particular importance are color displays which possess a color gamut capable of reproducing the many hues, chromas, brightnesses and saturations of natural objects, which perform at Television frame rates, and which address the needs of portable equipment, specifically in regards to battery power drain.
Electronic output display devices were popularized with the advent of Television, wherein images are typically presented at a rate of 30 frames per second to give an illusion of reality. While television was initially in black and white, the development of color technology has made color the preferred approach. More recently a variety of displays have been developed and are under development. In many prior art displays the generation of light by the display itself or the inclusion of a dedicated light source is the major power need, the major source of waste heat, and for portable equipment, the major battery drain.
This invention relates to utilizes and integrates a variety of technologies and disciplines, including:
Electrostatics:
While electrostatic phenomena were studied extensively during the earliest stages of electrical investigations, it has been the electrodynamic phenomena that have been dominant in the electrical industries. A notable exception has been the advent of xerography, in which electrostatic forces are employed in printing images on plain paper. Related disciplines have matured since the introduction of xerography in the 1950's. Both analytical and graphical methods for the analysis and mapping of electrostatic fields are well known and have been historically utilized in the analysis of electroscopes.
The utilization of electrostatic forces in conjunction with one or more stacks of colored, conductive, insulated, flexible membranes in a color display device as disclosed herein is a novel and an advantageous feature of the described invention.
Toner:
Technologies for the development and production of toners for monochrome and color Xerographic photocopy products are well established. Toner particles are fabricated as color pigments dispersed in a polymer. Particles range to as small as 0.04 micrometers diameter and utilize a variety of pigment colors. Color xerographic products routinely use Black, Cyan, Magenta and Yellow toners. Red Green and Blue toners have been developed for specialty products. Other developments have included magnetic toners, metallic toners and toners having specific brightness in ultraviolet and/or infrared wavelengths.
The utilization of either colored toner particles of color pigments imbedded within photo-resist materials whereby colored thin film patterns are obtained as described herein is novel and beneficial to the colored display herein described.
Color Science:
It has been demonstrated by prior art, in both xerography and offset printing that with black, cyan, magenta and yellow (CMY) dyes a full color palette is available. The additional colors of, red green and blue (RGB) can be made available either as separate toners or by dye-on-dye using the CMY toners.
The following color definitions are established:
BRIGHTNESS: Perceived quantity of visual flux PA0 HUE: Visual sensation to which an area appears to be similar to one of a set of standard colors, or combinations of these. PA0 SATURATION: The colorfulness of an area judged in proportion to its brightness. PA0 CHROMA: Colorfulness of an area judged as a proportion to brightness of a similarly illuminated area that appears White. PA0 GAMUT: The three-dimensional color space that encompasses all of the colors reproducible by the process. PA0 PALETTE: Specific colors available within the gamut.
The human eye perceives color at a resolution significantly lower than its perception of brightness. If a display is configured to match brightness resolution to the capability of human vision then color of pixels is not resolved visually but will merge into intermediate values of hue and chrome As a result of this feature of human vision a very large number of hues and chromas can be made available from the eight basic primary colors at the same time high resolution in brightness, is achieved. Because of this, a large color palette is obtainable with just eight common primary colors Black, Red, Green, Blue, Cyan, Magenta, Yellow, and White (KRGBCMYW) in dot next to dot.
In self luminous displays, as for example a cathode ray tube, adequate color rendition can be achieved by employing Red, Green, and Blue patches in a localized group utilizing brightness control. In the case of reflective displays, however, the rendition of color highlights demand that patches in any localized group be of the same highlight color. Side-by-side patches of different reflective primary colors as needed to develop a specific hue and chroma are incapable of adequate rendition of the brightness of highlight colors of many objects in nature. The present inventive color display device allows any or all color patches in a localized group to exhibit the same color, enabling bright white, yellow, cyan and magenta colors and their combinations. Those colors of lesser brightness, i.e. Red, Green and Blue and their combinations are, of course, also enabled.
The capability for all pixels of any local area to be any of the bright primary colors, Cyan, Magenta, and Yellow, allows the display of highlight colors in maximum brightness, as contrasted to the limited brightness available when they must be developed as dot-next-to-dot using the darker primary colors, Red, Green and Blue.
Pellicles:
A pellicle is a very thin polymer, or plastic film or membrane used commonly as a beam splitting component in optics and often utilized as an optical protective cover. Commercial pellicle beam splitters are available with thicknesses from 2 micrometers to 8 micrometers and thicker. A typical substrate material is nitrocellulose and they are readily coated with a variety of metals or polymers. Any of several common polymers can serve the function of a pellicle. Thus, for example polyester (e.g. Mylar, a du Pont tradename) is available in thicknesses as thin as of the order of 2 microns, and is readily coated.
Patterned multi-layer coatings on a pellicle, including conductive traces for data transmission and voltage distribution means as well as interconnectivity means, as discussed herein relative to the inventive color display device are novel and enable beneficial features. The inclusion of mechanical features including flats, grooves, notches, ridges, and/or bumps for mechanical and electrical mating and alignment of a fiber electrode to a pellicle is novel herein and provides a beneficial feature of the presently described inventive device.
Fiber optics:
Both glass and polymer fibers are used extensively in the communication industry. Methods are well in hand for volume production of both multi-mode and single mode fibers. Single mode glass fibers typically exhibit the extremely precise characteristics required for single mode laser propagation. Glass fibers are commonly drawn at near molten temperatures from a glass preform. Fibers of various cross section profiles are producible by utilizing a preform that is a composite of two glass materials, one of which being relative soluble in a given solvent, while the other is highly insoluble. In the process of drawing, the fiber assumes a smooth round shape preserving the distribution of constituent glasses of the preform. A subsequent etching process removes the soluble glass, leaving the insoluble glass having the desired profile.
Fabrication of a glass fiber having a flat surface and a groove as described herein for mating and alignment is new and novel. The mechanical mating and alignment of a pattern on a glass fiber with a corresponding pattern on a pellicle is an inventive and beneficial feature of the herein-described invention.
Kinematic Assembly:
Is well known that six degrees of freedom are necessary and sufficient for locating a mechanical object in its three spatial positions and its three angular positions. This feature is the basis of all precision assembly, both mechanical and optical.
The mating and alignment of coating patterns on a glass fiber to corresponding coating patterns on a pellicle wherein kinematic alignment is achieved over each of a plurality of localized regions as described herein is a new and novel beneficial feature of the described invention.
Silicon Electronics:
Electronics is dominated by silicon technology, and comprises of a host of related and mutually supporting technologies, including materials, masks, resists, and echants. A variety of dopants are utilized to provide specific physical and electronic functions within the silicon. Electronic devices are most commonly generated in bulk silicon. However, electronic devices are also generated within silicon that has been grown by epitaxy upon an insulator, commonly, sapphire or glass. In the case of glass, silicon grown epitaxially on fused silica allows the as-grown silicon to be annealed at a temperature sufficiently high to result in polysilicon, which exhibits electronic properties superior to the as-gown silicon. Photoresist materials are commonly used and typically comprise a polymer to which optical sensitivity has been incorporated by an additive. In some materials the resist becomes insoluble under the influence of optical flux, while in other resists optical flux induces the resist to become soluble where unexposed resist remains relatively insoluble. Both types of photo resists are widely used in the electronics industry in patterning silicon and other substrates for subsequent development and etching.
The fabrication of thin film transistor electronics within a silicon coating on a glass fiber is novel and provides a beneficial feature of the invention and is further applicable to electronics in general. The inclusion of mechanical features within the coatings on a glass fiber is inventive and is an advantageous feature of the invention.
Display devices based upon electrostatic attraction of a thin, insulated dielectric membrane have been disclosed in a number of prior art patents, including: U.S. Pat. Nos. 3,897,997; 4,094,590; 4,105,294; 4,160,582; 4,229,075; 4,336,536; 4,468,663; 4,747,670; 4,831,371; 4,891,635; and 5,667,784. Without exception these provide a monochrome display and fail to provide for color.
Printing and display technologies have invariably emerged as monochromic. Color technology has subsequently followed. When color has been available it has been preferred, both for esthetic reasons and for the additional information which can be displayed. The present inventive display device provides this important beneficial feature of color that is lacking in the above referenced prior art.
A prior art color display device is disclosed in U.S. Pat. No. 5,638,084. In '084 the color is provided by color pixels which are necessarily either black or of a single color. Any single pixel of the display cannot exhibit a selection of color. The color palette must be achieved by side-by-side patches that are each of a single color or are black. The unavoidable result is that color highlights are not available. In '084 optical paths to colored patches can optionally be covered with a black shutter or uncovered. A typical four-patch group (FIG. 2 of '084) comprises Red, Green, Blue and White patches. Black can be displayed for any of these by covering the patch with a shutter. A pure color of Red, Green or Blue is achieved by uncovering one patch of the four-patch group, leaving the other three patches black. However, maximum brightness is limited to one-quarter of what it would be if all four patches of the group showed the pure color. In the generation of the pure highlight colors of Cyan, Magenta and Yellow two color patches of the four patch RBGW group are uncovered leaving two patches showing black. The two uncovered patches together provide the brightness of a single patch of the pure highlight color. Again maximum brightness is only one-quarter of what it would be if all four patches of the group showed the pure color. In '084 White is achieved by uncovering the one White patch of the four-patch group and all three of the color patches. The brightness of the three uncovered color patches, taken together, is equivalent to that of a single white patch. The resultant brightness is only half of that available if all four patches were white. As a result the brightness of displayable White is limited to a shade of gray. Because of the above limitations inherent in '084 brightnesses, chromas, hues, and saturations of many natural objects in ambient illumination cannot be faithfully reproduced.
Prior art color displays that are self-luminous are typically brightness limited and cannot provide adequate luminance under bright ambient conditions, such as bright sunlight. The present inventive color display is functional under any bright ambient condition. In outdoor use it will emulate the brightness of a sign or a billboard in bright sunlight. As in any reflective display, as for instance a book, external illumination must be provided.
The ability of any color pixel or patch to show any of the colors of the color primary color palette is an advantageous feature of the present inventive color display. Chromas, hues brightnesses and saturations of natural objects in ambient illumination are faithfully reproducible for viewing in ambient illumination.
It is an object of this invention to provide a color display device using an assembly of stacks of voltage positionable colored membranes whereby each pixel color is selectable from a a palette of primary colors and wherein all pixels of the display are, optionally, able to assume any color of the primary color palette.
It is a further object of this invention to provide a color display device wherein the color highlights of natural objects in ambient illumination can be displayed.
It is another object of this invention to provide a high resolution, high brightness color display device wherein neither display self-brightness nor a dedicated illumination source is required, but wherein ambient illumination is utilized to view the display.
It is yet another object of this invention to provide a color display device upon which imaginal data is displayable at frame rates compatible with typical television and/or computer displays.
It is an additional object of this invention to provide a color display that is viewable in high ambient light conditions, such as bright sunlight.
It is yet another object of this invention to provide a non-self-luminous color display where by battery requirements for portable equipments are minimal.
It is a further object of this invention to provide a color display device in thin format wherein a printed page is emulated.
It is an additional object of this invention to enable "Picture on the Wall" television.
It is yet another object of this invention to provide a color display device that maintains the display of a color image when the display device is disconnected from sources of power.
It is a further object of this invention to allow a stored image display to be recovered as a data stream by reconnecting the display device to sources of power and synchronization.
Other objects and attainments, together with a fuller understanding of the invention will become apparent and appreciated by referring to the following description and claims taken in conjunction with the accompanying drawings.